First login to you client portal here:

Go to the return email section 

Make the changes you would like to see in the email using the editor

Set the Allow sending drop down to Customised. and hit save. 

If you would like to make more advanced changes you can change the HTML. Please always ensure the email has the following tags within it or the customer will not be able to get return labels. {{LOGO_URL}} {{LABELPDF_URL}} {{TRACKING_URL}} 

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